The present invention relates to an absorbent article such as a sanitary napkin, a panty liner or an incontinence pad, which article is intended to be substantially accommodated within a user""s panties and comprising a first absorbent part and a second part, whereby both the first part and the second part have a substantially elongate shape with a longitudinal direction and a transverse direction, with each part presenting two end portions, whereby the two parts are mutually joined solely at their end portions.
A basic requirement for an absorbent article such as a sanitary napkin or the like is that the article must be shaped in such a manner that it can collect and absorb all discharged bodily fluid.
Since, for example, sanitary napkins are intended to be accommodated within a pair of normal panties, they are relatively small and, above all, often rather narrow. There is therefore an obvious risk that by misplacing such an article within the panties or by it being deformed during use, it will not present a sufficiently large receiving surface for the discharged bodily fluid.
For example, it is not uncommon that the absorbent article is placed by mistake too far forward or too far backwards or offset somewhat transversely. Another commonly occurring reason for bodily fluid to leak past an absorbent article and to soil the user""s clothing is that the article is compressed between the legs of the user and thus becomes so narrow that the surface available for absorption becomes insufficient. Neither is it unusual for the side edges of the article to become folded over the surface of the article, thereby reducing the available surface.
An absorbent article of the type under consideration is generally maintained in the panties of the user by means of self-adhesive glue and/or a friction coating. When placing the article in the panties, it is difficult to obtain a placement which is optimal in relation to the body of the user. Normally, the crotch portion of the panties is used to determine where the article is to be placed. However, since panties are manufactured in a surprisingly large number of different models and sizes, the position and shape of the central portion provides an extremely unreliable indication of where in the panties an absorbent article should be positioned.
Another reason why leakage arises in absorbent articles intended to be attached within the user""s panties is that the article moves together with the panties rather than following the body movements of the user. This implies that when the user moves, the position of the panties and thus that of the absorbent article may be changed in relation to the user""s body.
A further complication in connection with absorbent articles intended to be accommodated within a pair of panties is that the quality of the panties is often very poor. Many users of sanitary napkins or the like want to avoid ruining their best underwear through staining due to, for example, menstruation blood and therefore use old, worn-out panties with poor elastic and poor fit during the critical period. This of course increases the likelihood of a gap arising between the user""s body and the absorbent article. There is therefore a clear risk that fluid may leak out between the body and the absorbent article.
Previously, it was common to attach absorbent articles such as sanitary napkins to a girdle which held the article in contact with the user""s body. The advantage with such girdles was that the absorbent article, during use, was always in contact with the body and could intercept discharged liquid as soon as it left the user""s body. The risk that liquid would leak out through gaps between the article and the user""s body was thus minimal. However, the girdles were regarded by the users as being awkward and difficult to use and could be difficult to conceal under normal clothing. Today""s users have become used to simply and quickly being able to attach the absorbent article within their panties and no longer accept the need to use girdles.
In order to reduce leakage which arises when absorbent articles are compressed between the user""s legs, it has become customary to provide the absorbent articles with particular attachment flaps. By way of example, it is known from SE 455,688; U.S. Pat. No. 4,285,343; EP 130,848; EP 134,086 and U.S. Pat. No. 4,608,047 to provide sanitary napkins with flexible side flaps or wings which project from the longitudinal side edges. Such side flaps are intended to be folded around the leg openings of the user""s panties during use and affixed to the outside of the panties. The side flaps themselves provide protection against side edge-leakage and staining of the panties. In addition, deformation of the absorbent body of the sanitary napkin is counteracted due to the fact that the napkin is fastened between the leg openings of the panties and, during use, is maintained in an extended state therebetween.
A considerable disadvantage with equipping absorbent articles with such attachment flaps is that many users feel that it is embarrassing that the attachment flaps, during use of the article, are visible on the outside of the panties. This also implies that absorbent articles with such attachment flaps cannot, for example, be used when the user is wearing a swimming costume.
Another disadvantage with attachment flaps is that they are relatively cumbersome and require a great deal of dexterity to be able to be fastened in a correct manner about the leg openings of the panties. Particularly with attachment flaps which extend along a long portion of the side edges of an absorbent article, it can be virtually impossible to fold the attachment flaps around the curved leg openings of the panties without chafing and ugly creases being created in the attachment flaps.
To improve the leakage security, it has been proposed in EP 0,067,465 to manufacture a two-piece sanitary napkin in which the two pieces are mutually attached only at their end portions. The lower piece is attached to the user""s panties and the upper piece contacts the user""s body. It is meant that the pieces, during use, should be able to move somewhat with respect to each other. However, the displaceability between the pieces is greatly restricted and the known sanitary napkin is still dependent on movement of the panties. Furthermore, there is no assurance that the upper piece will be maintained in contact with the user""s body during use.
A further two-piece absorbent article is described in PCT/SE96/01061 in which the two pieces are moveable with respect to each other. This known article also has restricted displaceability between the pieces and this is, to a certain extent, dependent on movement of the panties.
With the present invention, however, an improved absorbent article is provided of the type mentioned in the preamble.
The liquid-impermeable casing layer 5 can be any soft and pliable material with sufficient resistance to liquid penetration. Examples of such materials are thin, flexible plastic films, denser nonwoven material, hydrophobic textile materials or paper layers, liquid-permeable materials with a liquid-impermeable coating, or the like. It is generally no disadvantage if the liquid-impermeable casing layer 5 be gas and vapor permeable since, in this manner, the sanitary napkin exhibits certain breathability, something which contributes to increased comfort during use.
An article in accordance with the present invention is primarily characterized in that the second part of the article is curved in the longitudinal direction and presents high resistance to flexing along flexure lines parallel to the transverse direction of the article, both in a wet and a dry condition, and in that the first part, in a non-influenced condition has a lesser extension in a longitudinal direction than the second part and is provided with at least one elastically extensible region in the longitudinal direction.
The stiffness or the resistance to flexure in the second part must be so high that the tensile forces from the extended first part do not cause breakage or creases in the second part. The stiffness can be attained by lamination of a plurality of components whose combined stiffness is sufficiently high, or by using a particular stiffness-enhancing component such as an insert of rigid plastic or metal.
The second part can be extremely stiff and may for example be made from some sort of metal or hard plastic which remains substantially uninfluenced by the tensile forces from the first part and by those forces which arise during use of the article. Such an extremely stiff second part must be preshaped so that during manufacturing of the article it is provided with a curvature which approximately corresponds to the curvature in the crotch region of the user, from the lower portion of the abdomen backwards towards the bottom.
Even though a static second part may function satisfactorily, it is nevertheless beneficial for several reasons to use a more flexible second part. Thus, the second part can consist of, or comprise, a stiff yet flexible bar, rod or similar elongate shaping element of plastic, metal or the like. Of course, a plurality of such shaping elements may be included in one and the same article, for example a plurality of substantially parallel stiff strips or rods.
Such flexible yet stiff shaping elements can be manufactured in a flat condition and be given a desired curvature at the same time that the first part is attached to the second part. The tensile force in the elastic first part should therefore be adapted to the stiffness of the second part so that the second part, as a result of the pretension in the first part, is given a curvature which substantially corresponds to the curvature in the user""s groin. The first part can be attached to the second part by the manufacturer.
Alternatively, the two parts can be separate or only joined at the one end portion when the absorbent article is delivered to the user. This provides the advantage that the article can be packaged in a substantially flat condition, something which makes the article easier to handle and which saves space and packaging material.
According to a preferred embodiment, the first part has at least in each one end portion a lesser extension in the transverse direction than in a region situated between the end portions of the first part, whereby the connection between the first part and the second part has high rotational mobility about a longitudinal axis through the article.
The second part of the absorbent article can be totally non-absorbent or comprise a greater or lesser quantity of absorbent material depending on whether the second part is expected to contribute greatly to the absorption capacity or merely provide extra leakage protection.
The absorbent article is suitably provided with attachment means for attaching the article to the user""s panties. For example, the attachment means can be in the form of self-adhesive glue on the second part, over a surface which during use is intended to face towards the user""s panties.
Another suitable attachment means which can be used individually or together with adhesive or hook-and-loop type fasteners on the second part of the article are attachment flaps arranged on the side edges of the article. Such attachment flaps are provided on the second part along at least a region of each side edge on the second part, whereby the attachment flaps are intended during use to be folded around the leg openings of the user""s panties and are provided with means for attaching the flaps to the outside of the panties. Suitable means for attaching the flaps to the outside of the panties are, for example, glue surfaces, hook-and-loop surfaces, snap fasteners or the like. Furthermore, it is possible to use attachment flaps of the type which automatically clamp themselves about the side edges of the panties. Examples of such attachment flaps are given in WO 92/07537 and WO 92/07536. These documents describe attachment flaps which are arranged on the lower side of an absorbent article with the free ends of the flaps being directed towards the longitudinal centerline of the article. Such attachment flaps work extremely well with a stiff article which is curved in the longitudinal direction since the curvature contributes to maintaining the attachment flaps pressed against the underside of the article.
In accordance with the invention, the first part is elastically extensible. To achieve elastic extensibility, the first part may comprise an elastic member such as an elastic thread, an elastic strip, piece of material or the like which is elastically extensible at least in the longitudinal direction of the article and which is situated at at least the one end portion, in which manner the first part is elastically attached to the second part.
The first part can furthermore comprise one or more elastic members extending along the entire length of the first part.
The absorbent article is advantageously provided with an upraised portion on the first part. The upraised portion is thereby arranged so that it projects from a central portion of the surface on the first part which, during use, is intended to face towards the user.
The constituent parts of the absorbent article can be releasably joined at at least the one end portion. Such releasable joining can be achieved using complementary fastening means such as hooks and loops, buttons and button-holes, snap fasteners, hook-and-loop type surfaces, tie straps or the like.